Legstasd e



L. F. FULLER.

RADIOTELEGRAPHY,

APPLICATION FILED SEPT. 4, 191 7.

Patented July 8, 1919a INVENTOR 4 TTORIVEKS LEONARD F. FULLER, 0:5 SAN FRANGISCG, CALlFORNlA, ASSIGNOR TO FEDERAL TELEGRAPH COMPANY, 3F SAJf-I FRANCESCU, CALIFGRNIA, A CORPORATION 61* CALIFOFJHA.

REBEGTELEGRAPHY.

Application filed September 1917.

T 0 all whom it may concern Be it known that I, LEONARD it. FULLER a citizen of the United States, and a resident of the city and county of San rancisco and State of California have invented certain new and useful Improvements in Radiotelegraphy, of which the following is a specification.

The invention relates to means for signaling and particularly to means or" signaling with are radio transmitter An object of the invention is to provide means for signaling involving interrupting and reestablishing the arc.

Another object of the invention is to provide means for interrupting and reestablishing the are by varying the length of the arc gap.

The invention possesses other advantageous features some of which, with the foregoing, will be set forth at length in the following description where I shall outline in full that form of the invention which I have selected for illustration in the drawing acconipanying and forming part of the present specification. it is to be understood however, that the invention as expressed in the claims is not limited to the specific embodiments shown in the drawin The drawing is a diagrammatic represen tation of the signaling system of my invention.

T he transmission system comprises an arc oscillation generator, including the electrodes :23 between which the arc is formed. Que of the electrodes, preferably the negative electrode 8, is grounded and the other elect-rode 2 is connected to the antenna through the variable inductance coil 3irect current is supplied to the arc radio generator by the generator 6 and choke coil 7 is arranged in the lead 8 which is connected to the electrode 2. The are subjected to a strong transverse magnetic field produced by the magnet coils 9 which may be separately excited or arranged in series in the lead 8.

aigualiug is accomplished by varyiu the length of the are gap to extinguish and ignite the arc and this is preierabl acconr plished by moving one of the elec-trodcs: in the present construction, electrode 2 hcing movable. in operation, the length of the are gap is increased tosuch distance that Fateriteri July s, 3,,

Serial Trio. 139,522.

the are goes out and then the electrodes are brought sutliciently close together to re'e'stahlish the arc and are then separated to the position of proper oscillating arc lengtln at which time the radio energy vaves are transmitted. The individual signal is then terminated by increasing the length of the arc gap to extinguish the arc. These various epcratious are performed automatically and at telegraphic speed, and signaling is accoinplished with a transmission key in the usual manner:

Secured to the electrode 2 and insulated therefrom is a solenoid plunger or core 12- which is movable in a direction to increase the length of the are gap by the spring 1 5 and is movable in the opposite direction hv the effect of the current iiowing in the sole noid 1-1. The solenoid is arranged in series with the battery 15 and the signaling l 16 which, when depressech closes the circuit, and causes the electrode 2 to be moved to shorten the arc gap. In order to reignite the are, the electrodes must be moved 1;;11Cl1 closer together than their position of proper oscillating arc length and then they must be separated to such position. Stops are provided for halting the movement iii the electrode 2 when it reaches the arc ignition position and for halting it when it reaches the position of proper oscillating arc length and also for stopping it in its positioii greatest are gap length. An adjustable screw 17 arranged to contact with an on the plunger limits the backward movement of the plunger and an adjustable se n? 19 adapted to contact with e metallic ear arranged on and insulated ironi the phin limits the forward moveii'lent of the plungi i. iii-ranged in the solenoid circuit is a spring pressed switch 2:2 adapted to be opened hy the electroinaguet 23, arranged in series with the battery 24:, the car 21 and the stop li so that when the electrode has moved sufiicient distance to ignite the are, the contacts] and 19 are brought into engagement; closing the circuit through the clecti-oniagnet 23 and opening the switch rm i is to be On the backward movement of the plunger 12, the car 18 contacts with the core 25 which holds the electrode 2 in proper position to establish the proper oscillating arc length. On the forward movement of the plunger 12 from its rearmost position, the plunger 25 must be depressed to permit the ear 18 to pass and this is accomplished by connecting the solenoid 26 in parallel with the solenoid 14, so that when the solenoid 26 is energized simultaneously with solenoid 1 1 and the core 25 is lowered from the path of the car. When the switch 22 is opened, the spring 27 moves the core 25 into position to engage the backwardly moving car 18.

Means are also provided for removing the core 25 from the path of the car 18, to permit the arc gap to be lengthened to in terrupt the arc. Surrounding the solenoid 26 is a solenoid winding 28, in series with the battery 29 and the key contacts 31 and When the key is released, after having been depressed, the contacts 31 and 32 are brought into engagement closing the circuit through the solenoid withdrawing the core Signaling is therefore accomplished at telegraphic speed by the operation of the key 16, the depression of the key serving to cause a radio frequency wave train to be transmitted, the duration of the train depending upon the length of time that the key is held depressed. The depression of the key causes the electrode 2 to be moved from the position shown, to the ignition position 2 and thence to the oscillating arc position 2". As the electrodes wear, the length of the arc is adjusted by the nut 33 engaging a screw 3 1 secured to the normally stationary electrode 3.

I claim:

1. An are system for radio signaling comprising two electrodes between which an are formed, normally spaced apart a distance greater than the arc length, electromagnetic means for moving one of said electrodes relatively to the other whereby the arc is ignited, and the key for controlling said electro-magnetic means.

2. An arcsystem for radio signaling comprising two electrodes between which an arc is formed, electro-magnetic means for bringing the electrodes into proximity whereby the arc is formed and means for separating said electrodes to the position of proper oscillating arc length.

3. An are system for radio signaling comprising two spaced electrodes, a current supply connected to said electrodes, electro- 'magnetic means for bringing said electrodes together whereby an arc is formed, means for separating said electrodes to the posikey 16 is depressed, the

winding 28, thereby tion of proper oscillating arc length and means for lengthening the arc gap to extinguish the arc.

1. An arc system for radio telegraphy comprising two spaced electrodes, a current supply connected to said electrodes, a solenoid, a core connected to one electrode and associated with said solenoid, a circuit and associated with said solenoid, a circuit for said solenoid, the energizing of said circuit tendlng to move the one electrode toward the other, a spring resisting said movement and-means operative by the movement of said one electrode into arc igniting position with the other electrode, to open said circuit, whereby the spring separates said electrodes.

6. An arc system for radio telegraphy comprising two spaced electrodes, a current supply connected to said electrodes, a solenoid, a core connected to one electrode and associated with said solenoid, a circuit for said solenoid, the energizing of said circuit tending to move the one electrode toward the other, a spring resisting said movement, means operative by the movement of said one electrode into arc igniting position with the other electrode to open said circuit, whereby the spring separates the electrodes, and means for stopping the separating movement when the arc gap is of proper oscillating arc length.

7. An are system for radio telegraphy comprising two spaced electrodes, a current supply connected to said electrodes, a solenoid, a core connected to one electrode and associated with said solenoid, av circuit for said solenoid, the energizing of said circuit tending to move the one electrode toward the other, a spring resisting said movement, means operative by the movement of said one electrode into arc igniting position with the other electrode to open said circuit, whereby the spring separates the electrodes, means for stopping the separating movement when the arc gap is of proper oscillating arc length and means for releasing said stopping means whereby the arc gap is lengthened to extinguish the arc.

. In testimony whereof, I have hereunto set my hand at San Francisco, California, this 27th day of August, 1917.

LEONARD F. FULLER.

In presence of H. G. PROST. 

